This invention relates to fluid flow check valves, and in particular to one way fluid flow valves for inflating devices such as air cushions or balloons.
A number of check valves have been proposed for admitting air, water, or other fluids into a suitable fluid retaining chamber such as a cushion or balloon, while at the same time having the check valve prevent the escape of the admitted fluid during and after the fluid filling process. For example, U.S. Pat. No. 4,708,167 teaches a check valve for incorporation into devices such as a balloon toy. This check valve is formed from three plastic sheets (e.g. polyethylene), two sheets being heat sealed at their lateral edges to form the body of the valve, with the third sheet being heat sealed between the two body sheets to form the valving mechanism of the invention. A fluid channel between the third valve sheet and the two body sheets opens during fluid flow entering the balloon, and then closes due to air pressure within the balloon when entering fluid flow ceases.
U.S. Pat. No. 4,917,646 discloses two plastic sheets being bonded together to form a self sealing check valve for use primarily in non-latex balloons. The invention teaches utilizing non-coterminous plastic sheets having a barrier coating between said sheets at the inlet end of the valve, and also a positioning tab at the valve inlet to facilitate fabrication of the balloon-valve combination. Three additional prior art valves are discussed in FIGS. 6-8A similarly employing two or more plastic sheets comprising a one way fluid flow check valve.
Again in U.S. Pat. No. 4,983,138 a self sealing valve primarily for use with metallized toy balloons is disclosed. In this invention a plastic sheet is heat sealed within a balloon forming a two way valve which prevents fluid entry or release from the balloon when the balloon is fully inflated.
Additional self sealing check valves are described in U.S. Pat. Nos. 5,295,892, 5,144,986, and 5,308,163. A two plastic sheet check valve having additional structure for facilitating insertion of a gas supply nozzle for inflation of the balloon is disclosed in U.S. Pat. No. 5,295,892. In U.S. Pat. No. 5,144,986 a flexible plastic sheet having an aperture heat sealed between two flat plastic sheets to act as a flexible on/off flow diaphragm during fluid filling is disclosed. And U.S. Pat. No. 5,308,163 teaches a check valve comprising valve flaps defined and formed by a pair of heat sealed portions each composed of a plurality of curved heat seals coupled to each other in such a way as to approximately form a T-shaped valve flap at the junction thereof which serves as a fluid retaining segment.
While these check valve devices provide a variety of unique approaches to practical one way fluid flow valves, they do not address the simplification in fabrication, and innate reliability envisioned in the instant invention.
It is therefore a primary object of the present invention to provide an easily fabricated and economical fluid flow check valve.
Another object of the present invention is to provide greater reliability in fluid retention in an economically fabricated fluid flow check valve.
An additional object of the invention is to provide a fluid flow check valve that is capable of convenient connection to a source of fluid flow.
Still another object of the invention is to provide an economical method for fabricating a fluid flow check valve that can be conveniently altered to the degree of fluid pressure entry required by various check valve applications.